Press Z at the title screen to display the cheat menu.
Faster cheating
Cheats in the cheat menu (described below) are activated by the number of frags you have inflicted upon unworthy bots. To get more frags faster, copy your best game file to all 4 slots and load them all into the game. Voila! You now have 4x the frags in your name! Just go in and activate the cheats.
Faster Swimming
Instead of holding C-up when swimming, press and hold it until the stroke has nearly ended (i.e. until you become slower), then let the button go for about half a second and repeat.
Invincibility
Once you have unlocked the unlimited ammo cheat, choose the minigun into your arsenal before a game and whilst using it in-game, hold B. This gives you a impenetrable shield that holds any power up you have at the time for as long as you have the sheild on. Because you have unlimited ammo, this lasts forever and there is only way to get through it and that would defeat this cheat and so I'm not saying. Apart from that though, you are invincible.
List of all 50 medals
36 achievement medals for each level.
4 boss medals for defeating each boss.
7 task medals (must all be attain in 1 round):
1. Attain 15 frags in 5 minutes.
2. Attain 25 frags in 10 minutes.
3. Not getting any frags.
4. Not being fragged.
5. Killing yourself 5 times.
6. Coming in last.
7. Sniping 10 people.
3 lifetime achievement medals:
1. Attain 1,000 frags.
2. Be fragged 1,000 times.
3. Beat the two player co-operative trial mode.
Meals
There are fifty meals in the game.
Obtain 1st Bear Talisman
Complete the Warehouse level as Raptor.
Obtain 1st Cougar Talisman
Complete the Defcon 5 level as Mantid Drone.
Obtain 1st Coyote Talisman
Complete the Hopeless level as Guardian.
Obtain 1st Viper Talisman
Complete the Defcon 5 level as Elite Guard.
Obtain 2nd Bear Talisman
Complete the Defcon 5 level as Juggernaut.
Obtain 2nd Cougar Talisman
Complete the Warehouse level as Campaigner.
Obtain 2nd Coyote Talisman
Complete the Mystic level as Fireborn.
Obtain 2nd Viper Talisman
Complete the Wicked Dance level as Fireborn.
Obtain 3rd Bear Talisman
Complete the Defcon 5 level as Mantid Mites.
Obtain 3rd Cougar Talisman
Complete the Defcon 5 level as Lord of the Dead.
Obtain 3rd Coyote Talisman
Complete the Defcon 5 level as Oblivion Spawn.
Obtain 3rd Viper Talisman
Complete the Cathedral level as Mantid Mites.
Obtain Rank - Assassin
Acquire 20 medals.
Obtain Rank - Bane
Acquire 22 medals.
Obtain Rank - Brave
Acquire 8 medals.
Obtain Rank - Chieftain
Acquire all 50 medals.
Obtain Rank - Conqueror
Acquire 31 medals.
Obtain Rank - Darkling
Acquire 16 medals.
Obtain Rank - Deathwind
Acquire 27 medals.
Obtain Rank - Godhand
Acquire 45 medals.
Obtain Rank - Grunt
Acquire 4 medals.
Obtain Rank - Hunter
Acquire 12 medals.
Obtain Rank - Master
Acquire 34 medals.
Obtain Rank - Newcomer
Acquire 2 medals.
Obtain Rank - Scout
Acquire 6 medals.
Obtain Rank - Seeker
Acquire 18 medals.
Obtain Rank - Tracker
Acquire 10 medals.
Obtain Rank - Tyrant
Acquire 37 medals.
Obtain Rank - Warlord
Acquire 24 medals.
Obtain Rank - Warrior
Acquire 14 medals.
Obtain Rank - Warslave
Acquire 40 medals.
Unlock Acid Spit Attack for Mantid Mites
Complete the Crossroads level as Mantid Mites.
Unlock Adon's 2nd Skin
Acquire 4 medals.
Unlock Adon's 3rd Skin
Acquire 30 medals.
Unlock Boss - Bastille
Complete single player trial mode with Turok, Adon and Elite Guard.
Unlock Boss - Symbiont
Complete single player trial mode with Campaigner, Lord of the Dead and Juggernaut.
Unlock Boss - Syra
Complete single player trial mode with Raptor, Mantid Drone and Guardian.
Unlock Boss - Tal'Set
Complete single player trial mode with Mantid Mites, Oblivion Spawn, Fireborn and Mantid Soldier.
Unlock Campaigner's 2nd Skin
Acquire 10 medals.
Unlock Campaigner's 3rd Skin
Acquire 36 medals.
Unlock Elite Guard's 2nd Skin
Acquire 20 medals.
Unlock Elite Guard's 3rd Skin
Acquire 46 medals.
Unlock Fireborn's 2nd Skin
Acquire 12 medals.
Unlock Fireborn's 3rd Skin
Acquire 38 medals.
Unlock Guardian's 2nd Skin
Acquire 25 medals.
Unlock Guardian's 3rd Skin
Acquire 48 medals.
Unlock Juggernaut's 2nd Skin
Acquire 8 medals.
Unlock Juggernaut's 3rd Skin
Acquire 34 medals.
Unlock Laser Sight for Mag 60
Complete the Warehouse level as Guardian.
Unlock Lord of the Dead's 2nd Skin
Acquire 16 medals.
Unlock Magnet Upgrade for Scorpion Launcher
Complete the Crossroads level as Oblivion Spawn.
Unlock Mantid Drone's 2nd Skin
Acquire 6 medals.
Unlock Mantid Drone's 3rd Skin
Acquire 32 medals.
Unlock Mantid Mites's 2nd Skin
Acquire 25 medals.
Unlock Mantid Mites's 3rd Skin
Acquire 50 medals.
Unlock Mantid Soldier's 2nd Skin
Acquire 22 medals.
Unlock Mantid Soldier's 3rd Skin
Acquire 44 medals.
Unlock Oblivion Spawn's 2nd Skin
Acquire 14 medals.
Unlock Oblivion Spawn's 3rd Skin
Acquire 40 medals.
Unlock Rapid Fire for Assault Rifle
Complete the Warehouse level as Mantid Drone.
Unlock Raptor's 2nd Skin
Acquire 18 medals.
Unlock Raptor's 3rd Skin
Acquire 42 medals.
Unlock Secret Character - Adon
Complete single player trial mode with Lord of the Dead.
Unlock Secret Character - Campaigner
Complete single player trial mode with Raptor.
Unlock Secret Character - Fireborn
Complete single player trial mode with Campaigner.
Unlock Secret Character - Guardian
Complete single player trial mode with Elite Soldier.
Unlock Secret Character - Juggernaut
Complete single player trial mode with Guardian.
Unlock Secret Character - Lord of the Dead
Complete single player trial mode with Mantid Drone.
Unlock Secret Character - Mantid Mites
Complete single player trial mode with Lord of the Dead.
Unlock Secret Character - Mantid Soldier
Complete single player trial mode with Fireborn.
Unlock Secret Character - Oblivion Spawn
Complete single player trial mode with Juggernaut.
Unlock Secret Character - Raptor
Complete single player trial mode with Turok.
Unlock Shield for Minigun
Complete the Crossroads level as Fireborn.
Unlock Sniper Scope for Tek Crossbow
Complete the Crossroads level as Campaigner.
Unlock Turok's 2nd Skin
Acquire 2 medals.
Unlock Turok's 3rd Skin
Acquire 28 medals.
Unlock Upgrade for Boomerang
Complete the Warehouse level as Lord of the Dead.
Unlock Upgrade for Emaciator
Complete the Wicked Dance level as Oblivion Spawn.
Unlock Upgrade for Freeze Gun
Complete the Wicked Dance level as Juggernaut.
Unlock Upgrade for Grenade Launcher
Complete the Warehouse level as Juggernaut.
Unlock Upgrade for Jump Claw Attack
Complete the Crossroads level as Raptor.
Unlock Upgrade for Radioactive Flare Gun
Complete the Warehouse level as Oblivion Spawn.
Unlock Upgrade for Shotgun
Complete the Wicked Dance level as Lord of the Dead.
Unlock Warhammer Rocket Upgrade
Complete the Defcon 5 level as Turok.
Unlock Weapon - Assault Rifle
Complete the Crossroads level as Mantid Drone.
Unlock Weapon - Boomerang
Complete the Defcon 5 level as Adon.
Unlock Weapon - Chestburster
Complete the Warehouse level as Mantid Soldier.
Unlock Weapon - Emaciator
Complete the Wicked Dance level as Campaigner.
Unlock Weapon - Freeze Gun
Complete the Crossroads level as Guardian.
Unlock Weapon - Grenade Launcher
Complete the Crossroads level as Lord of the Dead.